daemontools: use Homebrew’s etc directory
daemontools: use Homebrew’s etc directory

Due to macOS’s file system restrictions from 10.15 and onwards,
using the `/service` directory is no longer a viable option.

This commit changes the service directory to `$(brew --prefix)/etc/service`.

One side effect is that Homebrew now creates the directory at formula
install time. This makes the caveat section simpler.

In case services are found under the old location at install time,
symlinks are created pointing to that old location.

Existing users are still encouraged to migrate their services to the
new location before they upgrade to 10.15+, hence the new caveat.

Closes #58237.

Signed-off-by: Sean Molenaar <2b250e3fea88cfef248b497ad5fc17f7dc435154@users.noreply.github.com>
Signed-off-by: BrewTestBot <8a898ee6867e4f2028e63d2a6319b2224641c06c@users.noreply.github.com>

jabenninghoff/homebrew-core,mbcoguno/homebrew-core,spaam/homebrew-core,nbari/homebrew-core,mahori/homebrew-core,filcab/homebrew-core,dsXLII/homebrew-core,JCount/homebrew-core,sjackman/homebrew-core,Homebrew/homebrew-core,maxim-belkin/homebrew-core,mfikes/homebrew-core,makigumo/homebrew-core,lembacon/homebrew-core,mahori/homebrew-core,chrisfinazzo/homebrew-core,mbcoguno/homebrew-core,dsXLII/homebrew-core,jvillard/homebrew-core,mbcoguno/homebrew-core,jvillard/homebrew-core,lembacon/homebrew-core,jabenninghoff/homebrew-core,Homebrew/homebrew-core,cblecker/homebrew-core,rwhogg/homebrew-core,uyjulian/homebrew-core,zyedidia/homebrew-core,Moisan/homebrew-core,maxim-belkin/homebrew-core,stgraber/homebrew-core,zyedidia/homebrew-core,nandub/homebrew-core,filcab/homebrew-core,jvillard/homebrew-core,adam-moss/homebrew-core,sjackman/homebrew-core,lemzwerg/homebrew-core,Moisan/homebrew-core,mfikes/homebrew-core,stgraber/homebrew-core,Linuxbrew/homebrew-core,nandub/homebrew-core,JCount/homebrew-core,lembacon/homebrew-core,Linuxbrew/homebrew-core,rwhogg/homebrew-core,spaam/homebrew-core,lemzwerg/homebrew-core,makigumo/homebrew-core,chrisfinazzo/homebrew-core,nbari/homebrew-core,uyjulian/homebrew-core,cblecker/homebrew-core,adam-moss/homebrew-core